The present disclosure relates to a centrifugal fan and an electronic device having the same.
A centrifugal fan is widely used as a cooling device in an electronic device. For example, most laptops use a centrifugal fan to dissipate the heat generated therein. An electronic device equipped with a centrifugal fan is required to be as calm as possible in order to make the user have a comfortable experience.
In order to reduce the noise of the centrifugal fan, conventionally, the designers focus on making improvements to the vanes, such as, changing the radial and axial dimensions of the vanes, changing the number of the vanes, changing the profile of the vanes, etc. However, these improvements to the vanes are limited by the narrow space in the volute casing of the centrifugal fan. What's more, the requirements on the wind speed, pressure and volume produced by the centrifugal fan also limit the design freedom of the shape, structure and number of the vanes. Therefore, after many years of improving to the vanes, it becomes hard to further reduce the noise through making improvement to the vanes.
Recently, some designers try to reduce the noise through optimize the distance/gap between the vanes and the volute casing, especially the gap around the volute tongue of the volute casing. Specially, the designers recognize that if the gap between the vanes and the volute tongue is too narrow, the centrifugal fan tends to “scream” and the noise level will be increased. Thus, designers begin to enlarge the gap between the vanes and the volute tongue. However, this brings another problem, i.e. the wind speed, pressure and volume are also reduced since some air cannot be effectively impelled or guided out of the exit of the fan but tends to circulate in the volute casing.
Therefore, there is a need for providing an improved centrifugal fan which on one hand may reduce the noise compared with the centrifugal fan in the prior art and on the other hand can produce at least same or even higher wind speed, pressure and/or volume. Accordingly, there is also a need for providing an electronic device with such a centrifugal fan.